A preview of Apple's typography, colours and sizes, adapted to both Duo displays
Does StyleGuide: Indie Dev HIG Tool work on iPhone Duo?
Yes. StyleGuide: Indie Dev HIG Tool's App Store page says it supports iPhone Duo, so the update is out. FoldHunt's editor hasn't seen it running yet.
- App Store confirmedThe developer, in the App Store release notes for version 3.1.1: content and toolbars are adjusted for the inner and outer displays, and the screenshot sizes now include iPhone Duo.
Adapted for the fold
We're waiting on details of exactly what StyleGuide: Indie Dev HIG Tool changes for the fold. Are you the developer? Tell us.
About StyleGuide: Indie Dev HIG Tool
StyleGuide lets developers preview Apple’s system type, colours and sizes before using them in an app. Version 3.1.1 adjusts its content and toolbars for both iPhone Duo displays, the release notes say, and adds the Duo to its screenshot sizes.
Evidence reviews
What we checked, when, and what the evidence establishes. Each record preserves the support label at that check.
· App Store page reviewed
App Store confirmed · iphone-duo
The App Store release notes for version 3.1.2 (released October 21, 2026) mention iPhone Duo: "In this update: - Added full support for iPhone Duo."
App version: 3.1.2.
Store text only: we haven't seen the app running, and the store page doesn't show how each pose is used.
View reviewed evidence ↗· Developer statement reviewed
Developer claimed · iphone-duo
Content and toolbars are adjusted for both Duo displays. Screenshot size references now include Duo.
App version: 3.1.1.
The developer's written claim only. No pictures or video of the app on the Duo were checked, and no build was tested.
View reviewed evidence ↗
Related guides
The best iPhone Duo apps so far (October 2026)
The apps worth installing now that iPhone Duo is on sale, from the apps Apple named as launch partners to indie apps whose developers have shown a real iPhone Duo layout, picked for what they do when you open the phone.
Do your apps work on iPhone Duo? What happens before they're updated
Every iPhone app opens on iPhone Duo, but only updated ones fill the inner display. What an app looks like before its developer adapts it, how to tell which are ready, and which popular apps have said so.
Is this your app?
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Sources: StyleGuide: Indie Dev HIG Tool on the App Store (apps.apple.com)
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